Method of and apparatus for forming glass tubes, rods, and the like



March 7,1939.. R BARNARD 2,150,017

METHOD OF AND APPARATUS FOR FORMING GLASS TUBES. RODS, AND THE LIKEOriginaL Filed Jan. 10, 1936 3 Sheets-Sheet l INVENTOR ATTO RN EY March7, 1939.

METHOD OF AND APPARATUS FOR FORMING GLASS TUBES, RODS, AND THE LIKEOriginal Filed Jan. 10, 1936 3 Sheets-Sheet 2 INVENTOR WVD u MBiAw/wpATTORNEY E LIKE 1936 3 Sheets-Sheet 3 R. Hv BARNARD Original Filed Jan10 METHOD OF AND APPARATUS FOR FORMING GLASS TUBES, RODS, AND TH March7, 1939.

Patented Mar. 7, 1939 UNITED STATES METHOD OF AND APPARATUS FORFORM INGGLASS TUBES, RODS, AND THE LIKE Randolph H. Barnard, Toledo, OhioApplication January 10, 1936, Serial No. 58,443 Renewed January 31, 193817 Claims.

This invention relates generally to the manufacture of glass articlesand has particular reference to a method and apparatus by which-glasstubes, rods and the like may be conveniently produced.

One of the primary objects of this invention is to provide a method andapparatus by which tubes or rods of various sizes, and of various crosssectional shapes may be produced.

Additionally, the invention contemplates the provision of an apparatusin which the several shaping and sizing devices used for imparting thedesired size and shape to the tubes or rods, may be readily removed andreplaced by devices varying in size and shape so that the apparatus canbe readily adapted to the forming of rods or tubing having any desiredcharacteristics.

The invention has as a further object the provision in an apparatus ofthe above mentioned character, of means'ior automatically controllingthe size of the tubing or rod being formed.

Still another object of the invention is to construct or cover thesizing and shaping bushings and the other portions of the apparatuswhich are contacted by the glass with a metal or an alloy which willresist erosion whereby the rod or tubing being formed will be maintainedat the proper size.

The invention contemplates further an apparatus whereby tubes ofdifferent sizes may be simultaneously produced from a single, glassreservoir or the like with the result that during a single day'soperation tubes or rods of various sizes and shapes may be produced fromthe glass melted in a single furnace.

The above and numerous other objects and advantages of the inventionwill become more apparent as the following description proceeds,particularly when reference is had to the accompanying drawings whereinFig. 1 is a. highly diagrammatic view showing an apparatus constructedin accordance with the teachings of this invention;

Fig. 2 is a diagrammatic sectional view along the line 2-2 of Fig. 1;

Fig. 3 is a diagrammatic plan view showing the manner in which a numberof apparatuses slightly modified from that shown in Fig. 1 may beassociated with a single forehearth;

Fig. 4 is a longitudinal sectional view taken substantially on the line4|. of Fig. 3;

Fig. 5 is a sectional view taken substantially on the line 55 of Fig. 4;

Fig. 6 is a fragmentary sectional view taken substantially on the line-8 of- Fig. 4;

Fig. 7 is a fragmentary sectional view taken substantially on the lineof Fig. 4;

Fig. 8 is a view similar to Fig. 6 showing a. different shape which theforming mechanism may assume; and

Fig. 9 is a fragmentary sectional view showing a slightly modifiedshaping and sizing device which may be utilized in the apparatus.

Before proceeding with a description of the details of construction ofthe embodiment of the apparatus shown in the drawings, the generalmethod will be first described, as will also the general features of oneform of apparatus which may be conveniently utilized for carrying outthe method.

Referring then to the drawings wherein like reference charactersdesignate corresponding parts throughout all views, and referring moreparticularly to Fig. l, the numeral l0 designates a feeding chamber fromwhich the glass to be formed into tubes or rods is drawn. This feedingchamber is provided with an outlet ii and associated with this outlet isan alloy bushing I2 having a tapered portion through which the glasspasses to the shaping and sizing device about to be described. v

The numeral l3 designates a sleeve which is mounted for rotation insuitable bearings- (not shown). Forrotating this sleeve there is fixedto the same a worm wheel I! adapted to be driven by a worm l which inturn is driven by a suitable motor l8.

At its one end the sleeve I3 is provided with an alloy bushing 20 whichassists in initially shaping the tubing or rod being formed. It is to benoted that the inlet end of the bushing 20 is en-' larged and that itsurrounds the tip end of the alloy bushing I! thus preventing theseepage of glass during operation. x

The initial shaping of the tubing or rod being formed is effected by thebushing 20 by virtue of the fact that the cross sectional shape of thepassage 2| through this bushing corresponds to the shape desired in thefinished product. Additionally, when round tubing or rod is being madeand the sleeve I3 is rotated, the bushing 20 prevents the rod or tubingfrom buckling. The bushing 20 is so mounted within the sleeve ii that itmay be readily removed with the result that bushings of various crosssectional sizes and shapes may be substituted one for the other to formtubing. or rods of various sizes and shapes.

At its opposite end the sleeve I3 is provided with a second alloybushing 25, having a central passage, the cross sectionalsize and shapeofwhich corresponds to the external size and shape desired in the tubingor rod being formed. Obviously, the cross sectional shape of the passage26 corresponds to the cross sectional shape of the passage 2|, while thecross sectional size of passage 26 is slightly smaller than the crosssectional size of passage 2|. As will later be brought out, the sleeveI3 is provided with suitable means whereby air may be supplied to theinterior of the same to properly control the temperature of the glasspassing through this sleeve.

Projecting into the feeding chamber and so positioned as to dischargeair into the passage 2| through the bushing 20, is a nozzle 30. Thisnozzle is of a shape corresponding to the cross sectional shape of thepassage 2|, but is of a size slightly smaller than the cross sectionalarea of the passage 2|, the difference in size between the nozzle andthe passage determining the thickness of the tubing wall when the tubingis being formed. This nozzle is likewise adapted to be readily replacedby a nozzle difiering in size and shape to the end that when a change inthe size or shape of the tubing being made is desired, a nozzle may beutilized which will correspond to the bushings and which are beingutilized.

The nozzle or mandrel controls the flow of glass through the bushing l2,and additionally this nozzle or mandrel is provided with a central airsupply passage 3|, which opens through the discharge end of the nozzleas clearly illustrated. Connected to the inlet end of the passage 3|, isa flexible air supply conduit 32, and this conduit is in turn connectedto a suitable source of air under pressure as for example, thecompressed air tank 33. A valve (not shown) controlled by a pinion 34 isarranged to control the flow of .air through the conduit 32 and thus thedischarge of air from the nozzle 3|].

The nozzle 30 is suitably mounted for movement toward and away from theinlet end of the bushing 20 and it is a feature of this invention thatmeans is provided for automatically moving the nozzle to adjust thespaced relation of the discharge end thereof from the bushing 20. Toaccomplish this result, there is provided an arm 35 which is fixed tothe nozzle and which has a threaded end 36 engaged by the inner threadedhub 31 of a worm wheel 38. It will be understood that the worm wheel issuitably journalled for rotation, but is fixed against movementlongitudinally of the arm 35 whereby upon rotation of the worm wheel thearm 35 and thus the nozzle is moved. A worm 39 driven by a motor 40 isprovided for rotating the worm wheel 38.

As thus far described, it will be apparent that if tubing is beingformed, the tubing designated by the reference character 45, will bedrawn through the bushings in the sleeve II by suitable mechanism (notshown). Externally, the tubing will be shaped by the bushings 20 and 25,

while the opening through the tubing will be.

formed by the air discharged by the nozzle 30.

It constitutes a feature of this invention that the size of thetubing'or rod being formed will be accurately and automaticallycontrolled. To accomplish this result there is disposed beyond thedischarge end of the sleeve l3a suitable gauging device designatedgenerally by the reference character50. This-gauging device comprises asuitable light sensitive element, such, for example, as a photoelectriccell designated by the reference character 5|. This light sensitiveelement is disposed on one side of the path of travel of the tubing 45,while disposed on the opposite side of the path oftravel of the tubingis a source of light 52, which, through a suitable lens system (notshown), directs light rays toward the light sensitive element. Thearrangement is such that the light sensitive element is partly shieldedby the tubing from the rays projected from the light source 52. This isdiagrammatically illustrated in Fig. 2 of the drawings and by referenceto this figure it will be apparent that if the external size of thetubing or rod 10 becomes increased or decreased, the amount of lightprojected onto the light sensitive element will be correspondinglydecreased or increased.

The light sensitive element is suitably interconnected with an amplifierand an electro- 15 magnet 58, the arrangement being such that as thedegree of illumination of the light sensitive element varies, theelectromagnet will be actuated.

Adapted to be reciprocated by the solenoid or electromagnet 58, is a rodand this rod is suitably connected to means adapted to control the speedof rotation of the sleeve I3, the supply of air to the mandrel or nozzle30, the tempera: ture of the bushings l2 and 20, and the spaced relationof the nozzle 30 from the bushing 20.

In order that reciprocation of the rod 60 may accomplish the aboveresults, this rod is provided with a plurality of rack teeth designatedby the reference characters 6|, 62 and 63. The first gear segment 6|engages a pinion 64 which in turn controls a rheostat 65. This rheostatcontrols the flow of current through conductors 66 to the motor "5 whichrotates the sleeve I3.

The second gear segment engages a pinion 68 35 which is arranged tocontrol a rheostat 69, this rheostat controlling the flow of currentthrough conductors 10 to suitable heating means associated with thebushings l2 and 20.

The third gear segment engages the pinion 34 which actuates the valvecontrolling the supply of air under pressure to the nozzle 30.

The motor 40 is a reversible motor and the direction of rotation of thismotor is controlled by a pole changing switch 15 of standardconstruction. For actuating this switch there is fixed to the arm 60 anarm or bracket 11 which is suitably 'connected to the switch 15.Suitable means (not shown) are provided for normally maintaining switch15 in a neutral or inoperative position, while additionally, provisionis made for a limited movement of the arm 11 even after it has beenmoved sufliciently to actuate the switch.

With the apparatus as thus far described, it will be understood thatglass drawn from the feeding chamber III will pass through the bushings20 and 25 and will thus be externally formed to the size and shapedesired. If the external shape of the rod or tubing is circular, thesleeve l3 together with the bushings 20 and 25 will be rotated whereasif the external shape of the rod or tubing is other than circular, thesleeve will preferably not be rotated.

Additionally, it will be understood that if glass rods are being formed,the nozzle 30 will not be utilized whereas if tubing is being -formedthis nozzle will be utilized to discharge air through the interior ofthe tubing to form the opening through the tubing in accordance with theusual practice. While in the diagrammatic showing of Fig. 1, the nozzle30 is illustrated as not being adapted for rotation, it is to beunderstood that this nozzle may be constructed in any desired manner,.or in the manner which will later 75 be brought out so that it mayrotate and that the speed of rotation of this nozzle may be controlledas will later be described.

If, for example, tubing is being formed,'it will be understood that asthis tubing leaves the sleeve l3, its external diameter will be gaugedby the device 50. Should the external diameter of the tubing vary fromthat desired, the light sensitive element will, through the amplifier55, effect an actuation of the electromagnet 59,

thus longitudinally moving the rod 69. The arrangement is such thatshould the diameter of the tubing drop below the size desired, therheostat 65 will be actuated to decrease the flow of current throughconductors 66 and to thus decrease the speed of rotation of the sleevel3 and the bushings 29 and 25. At the same time, the rheostat 99 willbe, actuated to decrease the flow of current to the heating elementsassociated with the bushings l2 and 20, thus lowering the temperature ofthese bushings and increasing the viscosity of the glass.

Additionally, the arm 60 moving toward the right will actuate pinion 34to reduce the pressure of the air supplied to the nozzle 39 and willactuate switch 15 causing motor 49 to move the nozzle 39 further awayfrom the inlet end of bushing 20. This will effect an immediate increasein the diameter of the tubing so that the tubing diameter will bebrought back to that desired. Obviously, should the diameter of the tubeincrease beyond the limits desired, the reverse of the above operationswill occur with the result that the diameter of the tubing will bedecreased.

While the operation of the apparatus as thus far described has beendescribed in connection with the forming of tubing of circular crosssectional area, it will be apparent that if tubing of non-circular crosssectional area is being produced. or if glass rods are being produced,either control of the motor l6 or the control of the nozzle 39 or bothwill be eliminated. The gau ing device 59 being directly responsive tothe cross sectional area of the tubing or rod being formed will functionthrough the several controls which have been described to maintain thetubing or rod to the size desired.

Beyond the gauging device 59 the rod or tubing may, if desired, besubjected to the action of a further forming and shaping devicedesignated generally by the reference character 80. As illustrated, thisdevice may comprise a housing ll, the ends of which carry removableshaping and sizing bushings 82 and 83. It will be understood that thepassages through these bushings correspond in size and shape to the sizeand shape desired in the finished rod or tubing, with the result thatthese bushings act to finally accurately shape the-rod or tubing beingformed.

The device 80 is preferably mounted for rotation and for movement towardand away from the sleeve IS in any desired manner (not shown) and therotative and longitudinal movements of the chamber 84, which is formedby the housing 8|.

Finally, a gauging device 85, similar to that previously described, maybe provided for finally gauging the rod or tubing, this final gaugingdevice being adapted either to supplement the control of the priorgauging device or to terminate the operation of the apparatus in theevent that the size of the rod or tubing varies too greatly from thatdesired.

As previously mentioned, it constitutes a feature of this invention thatduring a single day's operation, there may be produced from a singlefurnace, a plurality of rods and tubes differing in cross sectional sizeand shape. Heretofore, glass tube and rod manufacturing plants have beenseriously handicapped in meeting sales demands. form, for example,cylindrical tubing of a certain size, and an order is received fortubing of a different size or for glass rods, it has been necessary, ifthe desired rod or tubing is not in stock, to shut down the furnace,permit the forming mechanism to cool and to then replace the formingmechanism with a mechanism capable of forming rod or tubing of the sizeand shape desired and to then start up the actuation of the furnace tomelt the glass therein.

The present invention contemplates the elimination of this disadvantageby associating a plurality of glass feeding chambers with a singlefurnace, whereby different sizes and shapes of glass rods or tubing maybe simultaneously made from the glass melted in a single furnace orwhereby, if desired, the operation of any one of the series of formingmechanisms utilized may be started or discontinued, as desired.

Referring then particularly to Figs. 3 and 4, the reference character 90designates generally a glass furnace which may be of any desiredcharacter whatever. This furnace is preferably provided with a dischargethroat or trough 9| adapted to discharge into a forebay 92 whichis'preferably located below throat 9| so that the glass drops from oneto the other. The forebay 92 may, as illustrated, be semi-circular inhorizontal cross sectional shape and may be provided with a plurality offeeding chambers 93 which project radially therefrom. A gate or valve(not shown) is preferably provided in the throat 9| whereby the supplyof glass to the forebay may be conveniently controlled or cut offentirely, if desired.

By reference to Figs. 3 and 4, it will be noted that the flow ofglassfrom the forebay to the feeding chambers is controlled by valves 95,there being one valve for each feeding chamber with the result that thesupply of glass to any feeding chamber may be cut off, as desired.Additionally, each feeding chamber is provided with a drain plug 99whereby it may be drained and with a gate 91 which controls the level ofthe glass in the forward end of the feeding chamber.

Thus during the operation of the apparatus any feeding chamber may beplaced in operation or taken out of operation at the will of theoperator and without necessitating the shutting down of the main furnace99, or the draining of glass from the reservoir 92. Additionally, eachgate 91 may be adjustedto vary the glass level in its respective feedingchamber and to thus adjust the pressure at which the glass is suppliedto the shaping bushing. Preferably those portions of the throat 9|,reservoir 92 and feeding chambers 93 which are contacted by the moltenglass, as well as the valves 95, gates 91 and the nozzles and shaping Ifthe tube forming machine is set to -by a suitable bracket III.

bushings are either covered with or formed of a platinum or like metalor an alloy which is highly resistant to the abrasive action of moltenglass. For example, if desired, an alloy containing from eighty toninety per cent of platinum and the balance rhodium might be utilized.In this manner erosion of the several elements by the glass iseliminated so that the glass from which the rod or tubing is made willbe free of foreign matter which might be worn from refractory walls.

Referring now to Fig. 4 it will be noted that the feeding chamber 33 isprovided at its forward end with an outlet opening I I, in which ismounted a tapered metallic or alloy bushing I2, through which the glasspasses to the shaping and sizing device, the same as in the firstdescribed form of the construction.

The numeral I3 designates the rotatably mounted sleeve, this sleevebeing provided with a gear I which is driven by a pinion IOI, thispinion being in turn driven from the shaft I02 by means of the beveledgears I03 and I04. The motor I5 for driving the shaft I02 is supportedon a suitable standard I05, this standard likewise providing suitablebearings for the shaft I02 and the pinion shaft I06.

That end of'the sleeve I3 which is adjacent the feeding chamber isjournalled in a bearing I I0 which is supported from the feeding chamberThe bearing is preferably formed in half sections as illustrated, inFig. 6, these half sections being secured together by bolts II2 wherebythe bearing may be taken apart and the sleeve readily removed.

For journalling the lower end of the sleeve I3",

there is provided a bearing I I3, this bearing being similar to thebearing H0, and being carried by the standard I05. As illustrated, thehub of the bearing.

As in the first described form of construction, the sleeve carriesbushings and these bushings having passages 2| and 25 respectively,which aidin shaping the tubing or rod 45". As previously mentioned,these bushings may be formed of a suitable alloy which is entirelyresistant to the abrasive action of glass or, if desired, the bushingsmay be provided with platinum linings, as designated by the referencecharacter II5, It constitutes a feature of this construction that thebushings 20* and 25" may be fixed for rotation with the sleeve I3 as bybolting them to the sleeve or gear I00 in the manner illustrated, or, ifdesired, the bushings may be fixed against rotation by bolting them tothe adjacent bearings H0 or II3, suitable bolt holes II5 being providedfor this purpose. Thus It will be apparent that the shaping and sizingbushings may either rotate with the sleeve I3a or may be held againstrotation, while still permitting the sleevell to rotate.

To provide for the fiow of air through the sleeve in the direction ofthe travel of the rod or tubing therethrough, the sleeve is provided onits inner surface with spiral veins I20 which, when the sleeve rotates,act to create a movement of air in the direction of the length of thetubing and in the same direction as the tubing is being drawn.Additionally, the sleeve is preferably provided with louver openings I2Ithrough which air may flow from a housing I22 which encloses the sleeveI3. This housing is secured to the bracket III so as to be fixed againstrotation with the sleeve. Exteriorly of the housing I22, the sle'eveisprovided with openings I23 through which the air supplied to theinterior of the sleeve may be discharged, while for supplying air to thelute; rior of the housing I22, for flow therefromint'o the sleeve, theremay be provided an air sup;v ply pipe I24, which may terminate withinthe housing in a suitable annular nozzle I25. It might 1 be noted atthis time, that, if desired, suitable coloring material might besupplied to the interior of the housing I22 to color the rod or tubingas it passes through the sleeve I3. I

As in the previously described form struction, there is provided amandrel or nozzle designated generallyv by the reference character thisnozzle being provided with the air discharge passage 3I adapted to besupplied with air under pressure by a suitable flexible hose (notshown). The mandrel is journalled for rotation in a suitable bearing I30which is carried by a bracket I 3I having laterally extending flangesI32 mounted for sliding movement in suitable slideways I33, the latterbeing carried by the structural framework of the feeding chamber.

As in the first described embodiment of the invention, it iscontemplated that the mandrel be movedtoward and away from the bushing20 upon variations in the size of the tubing or rod being drawn, and toaccomplish this, the rod 60 is provided with rack teeth I35, whichdrives gears I36 and I31, the latter engaging a rack I38 formed on thebracket I3I. It will be noted that this construction takes the place ofthe electric motor 40 previously described, and provides that uponmovement of the rod IiIJ to the right as viewed in Fig. 4, the mandrelwill be moved away from the bushing 20.

For the purpose of rotating the mandrel, there is fixed to the same aworm wheel I40 driven by a wormI4I mounted on a shaft I42. The shaft I42may be driven from an electric motor I43 through the bevel gears I44 andI45. While the motor I43 is shown as being carried by the bracketI3I,-it will be apparent that, if desired, the motor may be providedwith a flexible shaft arranged to drive the bevel gear I44.

As previously mentioned, it constitutes a feature of this invention thatnozzles of different size and shape may be substituted the one for theother and it will be apparent that with the construction as thus fardescribed, this may be accomplished by sliding the bracket I 3I upwardlyout of the slideways I33, and by then removing the nozzle from itsbearing I30 by first removing the nut I which is threaded on the mandrelbody at one side of the bearing I30. Thus the nozzle is mounted not onlyfor rotation and for movement toward and away from the first sizing andshaping bushing, but is also adapted'to be readily removed from itsbearing so that a nozzle differing in size or shape may be placed inoperation.

of con- I Beyond the lower end of the sleeve I3 there 7 e is provided agauging device 50 similar in all respects to the gauging devicedescribed in'conrlection with Fig. 1. Beyond this gauging device thereisprovided a further shaping and sizing It will be noted that this deviceis in the legs I56 of a substantially U-shaped memmer, the base I51 ofwhich carries a motor I58 which drivesa worm wheel I59 which is inengagement with a worm I66, fixed to the housing 6|".

For the purpose of supplying coloring material or the like to thechamber 84' within the housing 8|, the housing is provided with suitable openings I6I which register with 'anannular housing I62, in whichthe housing 6| is mounted for rotation. The desired material is suppliedto the annular housing I62 by a supply pipe I63.

For the purpose of moving the device 86 toward and away from the sleeveI3, there is provided a motor I65 which drives a pinion I66 inengagement with a rack I61 formed on the underface of the member I51.The members I56 in which the bearings I55 are formed are mounted forsliding movement by virtue of laterally extending flanges I68 which'areengageable in slideways I69 formed in the legs I16 of a U-shaped supportdesignated generally by the reference character "I.

Beyond the device 86 there is provided a final gauging device 85, whichoperates in a manner similar to the device 65 previously described;

It will be understood that the gauging device 56 is arranged as in themanner previously described, to reciprocate the rod 66. This rod carriessuitable rack teeth (not shown) which actuate rheostats also not shownfor controlling the flow of current to the wires 66 which lead to .themotor I6 and also the flow of current to wires 16" which lead to thebushings I2 and 26, for heating the latter. Thus as described inconnection with the embodiment of the invention shown in Fig. 1, whenthe rod 66' is reciprocated, the speed of rotation of the sleeve I3 willbe varied as will also the temperature of the bushings I2" and 26. Asalso previously described, the rod 66* has rack teeth 63 arranged toactuate pinion 34*, which in turn actuates the valve which controls thesupply of air to the mandrel 36.

In addition to the above controls which were effected by the rod 66 inthe embodiment of the invention shown in Fig. 1, the rod 66' is alsoadapted to control the speed of rotation of housing 6|, the movement ofthis housing toward and away from sleeve I3 and the speed of rotation ofthe mandrel 36. Thus rod 66 is provided with rack teeth I15 arranged toactuate a rheostat I16 which controls the flow of electric current tomotor I58, so that upon reciprocation of rod 66", the speed of rotationof housing ll and its associated bushings will be varied.

The motor I65 which is arranged to move the device 66* is a reversiblemotor and is adapted to be controlled by a pole changing switch I86which is of standard construction and similar to the switch 15. Fixed tothe arm 66' is an arm or bracket I62 which is arranged'to actuate theswitch I66 in the same mannfr as arm 11 actuates switch 15.

For the purpose of controlling the speed of rotation of the mandrel, therod 66 is provided with rack teeth I85 which actuate a rheostat I66 andthis rheostat controls the support of electric current to the motor I43which rotates the mandrel.

It is believed that the operation of the embodiment of the inventionshown 'in Figs. 3 through '1 inclusive will be apparent when consideredin connection with the description of the operation of the embodimentshown in Fig. 1. If the diameter of the tubing falls below the sizedesired, the rod 66 will be automatically actuated to decrease the speedof rotation of the sleeve I3 and thus of the bushings 26 and 25; todecrease the fiow of current to the bushings l2"- and 26 thus loweringthe temperature of these bushings and increasing the viscosity of theglass; to reduce the pressure of the air supplied to the nozzle 36 andto move the nozzle 36 further away from the inlet end of the bushing 26.Additionally, this movement of rod 66 will actuate rheostat I86, todecrease the speed of rotation of the mandrel; will actuate rheostat I16to decrease the speed of rotation of the housing 6| and its associatedbushings and will actuate switch I86 so that the device 66 will be movedcloser to the sleeve I3. This will effect an increase in the diameter ofthe tubing so that the tubing diameter will be brought back to thatdesired.

In passing through the device M, the rod or tubing is subjected to thefinal sizing and gauging actions of the bushings 82 and 83 and may alsobe colored, if desired, by admitting a suitable coloring material to thechamber 84. The rod or tubing is then again gauged by the device 85which may be arranged to terminate the actuation of the apparatus in theevent the tubing size varies too greatly from that desired, or which maybe arranged to modify the effective actuation of the means controlled bythe gauging device 56.

In Fig. 8, there is diagrammatically illustrated a modified form ofbushing 26b in which the passage 2I therethrough is square rather thanround. It will be noted, however, that also in this case the end of thenozzle 36 is preferably slightly smaller than the cross sectional areaof the passage 2I In Fig. 9 a further modification of the inventive ideais disclosed in which the sleeve I3 and spaced bushings 26 and 25 areeliminated and there is substituted therefore an elongated conicallyshaped bushing or shaping device designated by the reference character266. It will be noted that the glass drawn from the fixed bushing I2enters the larger end of the member 266 and in being drawn through thesame is accurately sized and shaped so that when the rod or tubingleaves the discharge end 26I of the member 266, it is of the size andshape desired. Themember 266 is mounted for rotation in a manner similarto the sleeve I3, and additionally, this member is preferably providedwith openings 262 so that air supplied to the interior of housing I22may act on the-rod or tubing being drawn to properly control thetemperature thereof. If desired, the

member 266 may be electrically heated in the same manner as member 26.

From the above it will be apparent that the invention provides meanswhereby from a single furnace a series of tubes or rods of various crosssectional sizes and shapes may be simultaneously produced. Additionally,the supply of glass to each feeding chamber may be cut off wheneverdesired, and the forming mechanism associated therewith may be changedto produce rod or tubing differing in size and shape from thatpreviously formed.

When tubing or rod circular in cross section are i being produced, theseveral forming bushings are preferably rotated, although it is to benotedthat it isnot essential that these bushings be struction. disclosedin Fig. 4 to have the bushing 20' rotate with the sleeve He, whileholding the bushing stationary, if such an operation is desired.Obviously, when rods or tubing having cross sectional shapes other thancircular are being produced, the several shaping and sizing bushings areheld stationary.

The discharge end of the nozzle is preferably slightly smaller than theinlet end of the first shaping and sizing bushing and additionally, thenozzle is so mounted that it may be readily removed and replaced by anozzle of a diiierent size and shape. The bushings 20 and 25 maylikewise be readily removed and other bushings substituted for the sameby virtue of the split bearings in which these bushings are located. Thefinal shaping and sizing bushings 82 and 83 are likewise adapted to bereadily removed from the device 80" with the result that by suitablychanging the bushings and the nozzle, tubing or rod of any desired sizeand shape may be produced.

It might be noted in speaking of substituting one series of bushings foranother, it is meant that the bushings will have different sized orshaped passages through them. In other words, it is a feature of thisapparatus, that externally the bushings are of the same size and shapeso that the elements in which they are mounted need not be changed whenit is desired to change the size or shape of the tubing being formed.

The electrical connections to the bushings I2 and 20 permit an accuratecontrol, of the viscosity of the glass and thus assist materially inregulating the diameter of the rod or tubing being drawn. Additionally,the electrical connections to the bushings 20 provide a means where- .bythe so-called wetting characteristics of the bushing may be controlledand in this manner the smoothness and polish of the rod or tubing beingdrawn may be regulated.

The fact that the bushings are formed of an alloy which is highlyresistant to the abrasive action 01' molten glass, or are lined withsuch an alloy, prevent the mechanical variations in tube diameters whichare usually encountered in the 4 use of bushings formed of clay orcommon metals.

While the invention has been described with some detail, it is to beunderstood that the description is for the purposes of illustration onlyand is not definitive of the limits of the inventive.

' ture of the sizing and shaping means upon varia- =tions in the size orthe rod or tubing from a predetermined desired size.

2. The method of forming glass tubes which consists in drawing the glassfrom a suitable source, initially shaping the glass as it is withdrawnfrom the source, rotating the shaping means, discharging air through thecenter 01' the glass being drawn, gaugin the size of the tube beingdrawn, and controlling the pressure of the air supplied to the interiorof the tube in dependence upon the actuation of the gauging means.

3. The method of forming glass tubes which consists in drawing the glassfrom a suitable source, sizing and shaping the glass as it is withdrawnfrom said source, rotating the'sizing and shaping means, discharging airunder pressure through the center of the glass being drawn, gauging thesize of the tube being drawn, and varying the speed of rotation of thesizing and shaping means and the pressure of the air supplied to theinterior of the tube upon variations in the size of the tubing from apredetermined desired size.

4. In an apparatus of the class described, a shaping bushing throughwhich the glass ,is drawn, a feeding chamber for feeding molten glassinto the bushing, and means including a light sensitive element forgauging the size 01' the tube or rod drawn through the bushing.

5. In an apparatus of the class described, a shaping bushing throughwhich the glass is drawn, a feeding chamber for feeding molten glassinto the bushing, a second bushing spaced from the first mentionedbushing adapted to engage the glass being drawn to shape the same, asleeve carrying both of said bushings, and means including a lightsensitive element for gauging the size of the tube or rod being drawnafter it has passed through said second mentioned bushing.

6. In an apparatus of the class described, a shaping bushing throughwhich the glass is drawn, a nozzle for discharging air centrally throughsaid bushing, a gauging device for gauging the external size of thetubing drawn through the bushing, and means controlled by said gaugingdevice for regulating the pressure of the air discharged through thebushing by the nozzle.

7. In an apparatus for forming glass tubing, a pair of spaced shapingand sizing bushings through which the glass is adapted to be drawn.means for feeding molten glass to one of said bushings, a sleevemounting said bushings, means for rotating said sleeve, a nozzle fordischarging air through the bushing to which the glass is initiallysupplied, a device for gauging the size of the tubing which is formed,and means controlled by said gauging device for controlling the speed ofrotation of the sleeve, the spaced relation of the hozzle to the bushingadjacent which it is located, and the pressure of the air discharged bythe nozzle.

8. In a machine for forming glass rods or tubes, a shaping and sizingbushing through which the glass rod or tubing is drawn, means forfeeding molten glass into said bushing, means for heating the bushing, adevice for gauging the size of the rod or tubing after it passes throughsaid bushing, and means controlled by said gauging device forcontrolling the temperature of said bushing.

9. In an apparatus for forming glass tubes or rods, a plurality ofspaced shaping and sizing bushings through which .the glass to be shapedis drawn, means for feeding molten'glass to one,

of said bushings, means for gauging the external size of the rod ortubing shaped by said bushings, and means for discharging a coloringagent into contact with the rod or tubing after it has been sized andshaped by the said bushings.

- 10. In an apparatus of the class described, a sleeve mounted forrotation, shaping and sizing bushings removably carried by the oppositeends of said sleeve, means for feeding molten glass into one of saidbushings, means for drawing the glass through the bushing into which itis fed and through the other bushing, and means for supplying coolingair to the interior of said sleeve.

11. In an apparatus of the class described, a sleeve mounted forrotation, said sleeve being provided in its sides with louver openings,shaping and sizing bushings removably mounted in opposite ends of saidsleeve through which the glass to be shaped is drawn, and means fordischarging cooling air into said sleeve through said louver openings.

12. In an apparatus of the class described, a feeding chamber for moltenglass, a bushing having a sizing and shaping passage through whichtubing to be shaped is drawn, means mounting said bushing at aninclination to the horizontal, a nozzle arranged to discharge air underpressure into the passage through the bushing, a gauging device forgauging the size of the tubing drawn through the bushing, and meanscontrolled by said gauging device for adjusting the nozzle toward andaway from the inlet end of the bushing.

13. In an apparatus for forming glass tubes or rods, a feeding chamberhaving a discharge opening through which the molten glass is drawn, abushing defining the discharge opening in the feeding chamber, a devicefor gauging the size of the tubing or rod drawn through the bushing, andmeans controlled by said gauging device for controlling the temperatureof said bushing to thus control the viscosity of the glass as it leavesthe feeding chamber.

14. In an apparatus of the class described,

a feeding chamber for molten glass, a series of spaced sizing andshaping bushings through which the glass is drawn, means for gauging thesize of the rod or tubing drawn through said bushings, means forrotating the bushings, and means controlled by the gauging means forvarying the speed of rotation of said bushings.

15. In an apparatus of the class described, a sleeve mounted forrotation, shaping and sizing bushings removably carried by said sleevethrough which the glass to be shaped is drawn, means for providing forthe supply of air to the interior of the sleeve, and spiral veinsdisposed within the sleeve adapted upon rotation of the sleeve to createa movement of the air therein in the direction of travel of the rod ortubing drawn through the sleeve.

16. In an apparatus for forming glass tubing,

'a feeding chamber from which the glass tubing is drawn, a nozzle fordischarging a fluid under pressure centrally through the tubing beingdrawn, a gauging device for gauging the external size of the tubingbeing drawn, and means controlled by the gauging device for regulatingthe pressure of the fluid discharged by the nozzle.

1'7. In an apparatus for forming glass tubes or rods, a feeding chamberfrom which the glass tubes or rods are drawn, a second chamber throughwhich the rod or tubing passes, and means for discharging a coloringagent into the second chamber into contact with the rod or tubes drawntherethroug'h.

RANDOLPH H. BARNARD.

